I have a single piece "true dual" setup a traded with another local tccoa-er (he needed cats, I didn't b/c my tbird is a track car). My old setup had the 2 stock cats, the center resonator, and a $20 cherry bomb at the end of a single pipe. My "new" setup consists of 3" pipes, two cherry bombs as the downpipes to replace the cats, an X-crossover in the center section, and two flowmasters at the end. The short answer is that it's too low.
* SCs and 3.8L NA cars have the same exhaust system.
* Single piece systems are a pain in the butt to move around (it's 15 feet of metal -- I had to borrow a friends subaru wagon and strap it to the roof to get it to my house).
* It's fairly loud and raspy. It makes this glorious blast sound when you lift off the trottle, the tune goes a little rich, and the fuel promptly explodes somewhere in the exhaust since there's not cat to catch and burn up this small amount of unburnt fuel. Glorious on a $500 racecar but NOT something I would find useful on a daily driver.
* The WORST thing about a true dual setup, IMO, is ground clearance. My car is already pretty low because of the suspension and tire setup (only 4.5" from the bottom of the car behind the front wheel wells) and I'm afraid I have lost even more clearance b/c of the cross pipe (maybe about an inch). What does this mean in practical applications? Here in SF we have the occasional speed hump that doesn't go across the entire street but is just divided into a few sections. Each is maybe a few inches high. The normal procedure is that you see one up ahead, you slow down (what the urban planners want you to do), and you straddle the hump with your wheels. I tried that with the tbird and this new exhaust -- once. The net result was that I heard this awful scraping sound as the x pipe scraped the hump.
This setup wouldn't be terribly streetable -- I'm even worried about off-track excurisions/debris on the race track. Oh well.
Recommendation: if you want to free up your exhaust system a little more, go to a muffler shop and have them replace your rear muffler for cheap. It will be throatier but not unbearable.
Personally, I'm not sure you will get any noticable performance gains to justify this $400 high flow cat setup and an independant muffler shop (not like a Midas) should be able to put something together for you for significantly cheaper. Even here in expensive CA (not only for the labor costs but also b/c all emissions equipment needs a CARB certification), I asked about a cat setup and was told that they could put replace cats for <$150.
That $400 could easily cover a splitport upgrade.
If you do go with the true dual setup (or desire to delete the resonator), I highly recommend that you heed my advice about ground clearance. Get them to run those pipes as close to the body of the car as possible (i.e.: no lower than the stock setup).
24 Hours of Lemons 2017 Sear Pointless Organizer's Choice
2018 Upgrade: does your TBIRD make Fritos? Mine does